Conservatives recently pushed legislation through the House that would prohibit same-sex marriages from being performed at military chapels. This prohibition would even apply to chapels that are located in states where same-sex marriage is otherwise recognized.
In 2009, conservatives overturned regulations that banned firearms in national parks. The logic was that people should be permitted to carry firearms in national parks located in states where it is otherwise legal to carry them.
Some conservatives want to apply state rules in federal installations, but apparently only if the state rules align with the conservative agenda. A true states' rights advocate would allow state law to apply to both same-sex marriage and firearms.